As dissolution phenomena were to be studied, the concentrations
considered here were approximately one order of magnitude
below those found in original inks. The final concentration used for
gallic acid was set at 2.35 103 mol L1 for all experiments,
which led to a solution with a pH between 3.4 and 3.5. The same
concentration of iron was then chosen for the solutions of Fe(II)
and Fe(III) sulphates. The concentration used for gum arabic suspensions
was also fixed at a unique value of 3.93 g L1
, so that
the proportions of iron and gum arabic correspond to a binder-rich
iron gall ink according to an ancient French ink maker’s book dating
from 1927 [30].
A